Beneteau Sense Quality Issues

[SaltyMonkey]

AVS is misleading because it is static and doesn't take into consideration environmental issues

[colemj]

Our boat has an AVS ~90* and we have no problem with that…

Mark

[robert sailor]

Yes Cats do have a low AVS but then again they are not designed to be self righting, if you go turtle, you stay there. That can also be an issue with super beamy boats as they can be just as stable upside down as right side up.

[Polux]

Yes, by being beamy means that they have a huge form stability to join to the RM provided by the ballast and that they are, like the cats, much more dificult to capsize then narrower boats with an overall smaller stability.

Regarding re-righting what counts is the proportion between the positive area of the RM curve and the negative area and that has nothing to do with beam but with the position of the CG.

Meaning that if a beamy modern boat with its huge stability needs a huge wave to be capsized, if it has a good Stability curve will need a wave 3 times smaller to put its back on its feet. It is this proportion that matters as well as the size of the wave needed to capsize it.

Who wants to be in a boat that is easily capsized even if it returns easily to its feet?

[colemj]

Originally Posted by Polux

Who wants to be in a boat that is easily capsized even if it returns easily to its feet?

Everyone who doesn't like, appreciate or even tolerate any different type.

Mark

[deluxe68]

Originally Posted by Polux

There are several ways to measure AVS, the one used by ISAF for racing gives lower numbers than the one used on European RCD, an ISO procedure. Regarding an ISO AVS a First 36.7 with standard keel has an AVS of 126º. For instance, and comparing what is comparable and equally in what regards ISO AVS, a Catalina 42 or 42MKII has an AVS of 105º.

What boat do you have? Do you know the ISO AVS?

The B/D of the boat can be misleading since the type of keel and draft have a big influence. A boat with a bigger draft an a torpedo keel needs much less ballast for the same RM, compared with a lower draft or a non bulbed keel. Even a bulbed keel needs more ballast if compared with a torpedo keel to have the same RM.

36.7, I just sold it, deep keel. BTW, the Euro model had @300-500 pounds more ballast than the one made in the USA. The 40.7 had a much higher B/D ratio, approx the same keel depth, designed by the same guy. Like I said earlier, the boat did not qualify for some offshore racing.

[robert sailor]

Lots of folks must really take some of this stuff personally. I understand justifying your individual choice and I also know that like religion very few people actually change their minds even when presented good information that runs contrary to their beliefs. Most Cats and beamy lightly ballasted boats are fine for typical trade wind sailing, hell you can sail a 1970's 20 foot racer cruiser across an ocean when all is well so no argument there. Getting unlucky in storm conditions I personally would make other choices but thats just me. I know 99% of these boats are running around the Med or in the Caribbean, that's what they were designed for and they do a wonderful job, whats not to like. How some of these designs would have fared in the 79 Fastnet race, well that's another subject.

[colemj]

Originally Posted by robert sailor

I know 99% of these boats are running around the Med or in the Caribbean, that's what they were designed for and they do a wonderful job, whats not to like. How some of these designs would have fared in the 79 Fastnet race, well that's another subject.

99% of all boats are probably running around in those places.

Why in the world would we, or many others, be in the Fastnet race with our boats? The boats actually IN the Fastnet didn't fare all that well. Your argument point here is a non-sequitar.

I am always amazed meeting people on heavy, rolly, slow, cramped, wet crab crushers who never leave protected cruising grounds yet spend hours extolling to me about how anything different is taking your life in your hands (and particularly expressing horrors about multihulls). I am further amused when they describe all of their slow, rolly, wet "passages from hell" - many of which we were out at the same time having a fast, steady, dry wonderful passage. I mean we have literally sailed the same passages at the same time only to hear them describe 180* opposite evaluations from our experience.

Yes, there is always "that storm". But I don't believe that the boat makes much difference in that case. The majority of recently abandoned boats were of the more traditional cruising types. The crew gives out before the boat.

Mark

[robert sailor]

Well to be frank I'd rather be in a Cat in a storm than a Benni Sense. I was introduced to Cat sailing by Blair on Capricorn Cat a 45 footer in the Marshall Islands. I was not a lover of Cats until I sailed that boat and I was a convert after that. We sailed across a lagoon doing close to 15 knots with little rooster tails. Later he passed us in open water and not that many boats we ran into could pass us the way he did and he did it very handily with little sail. Later he raced against us and we were on a 60 foot Willey and he could damn near go upwind with us and was much faster on a reach so that boat really opened my eyes.
We got whacked pretty good a few days out of New Zealand and until you have sailed in large breaking seas for a couple of days you can't appreciate how difficult it is to control the boat but it was hand steering for over 30 hours. I'm not a fan of crab crushers either but I like a boat that was designed for offshore use.

[Polux]

Originally Posted by colemj

..
I am always amazed meeting people on heavy, rolly, slow, cramped, wet crab crushers ... I am further amused when they describe all of their slow, rolly, wet "passages from hell" - ...
Mark

That old type designed hull, kind of Swan type of the 80's is still what some consider the most seaworthy type of sailboat around. Take a look at the beginning of the movie and consider that these guys are a professional big crew, expert sailors and even so they have to let go the spi.

http://vimeo.com/82631343

Consider also that it happened in a very benign sea. With waves increasing that roll it could have been a lot worse, even a severe knock down. When the boat is heavily heeled most of that stability is gone and the boat is much more susceptible to be capsized by a breaking wave, even a small one.

One of the reasons contemporary boat design went to beamy hulls with all beam pulled back was to prevent this possibility and the rolly behavior downwind. No way a boat with the hull of a Sense or Open boat type boat is going to do that, even with an inexperienced single sailor at the wheel or on autopilot.

[robert sailor]

I'm not sure which Swans your talking about but I'll assume an S&S design. The righting moment on most of these designs will be higher than the Sense and actually will continue to be much stiffer as they heel more. There are lots of pictures of the beamy French race boats from years ago that turned turtle and stayed there, not for a few seconds or a few minutes but just stayed there. Racers were rescued and some great stories were told while they lived upside down for many hours. After that they had to be tested upside down to ensure that they would right themselves and along came the canting hydraulic keel because without it they would not self right.

The Contessa 32 was the benchmark boat that was used in the large study done after the 79 Fastnet race, yachting's worst disaster. It had a self righting range somewhere around 156 degrees. There was a large fleet of these boats in that race and every one of them sailed the race and returned when lots of larger boats didn't. The Contessa was sailed around Cape Horn against the wind and current, hell of a little boat.
Beam is wonderful for initial stability but when lightly ballasted once it goes past a certain point it has little resistance to rolling. Some folks suggest they wouldn't sail their boat in a race like that but I'm sure none of the participants would have either had they known what was coming. 99% of the time any sailboat will make it across the oceans and they obviously do but some boats are pushing the design limits in my opinion when it comes to being truly designed for unlimited offshore use.

[robert sailor]

Polux,
I didn't see your movie but I'll make an assumption that the boat was under spinnaker and was rolling and started to lose control. I will believe that.. as these boats were optimized for sailing upwind. Many of these designs when raced hard could be a handful under chute and yes the narrow sterns certainly added to that control issue, no argument. I also agree that modern boats with the beam brought well back in the stern are much more controllable and faster off the wind than the Swans of the 80's.
This scenario, if my assumption is correct has got zero to do with self righting and overall stability in large seas. These older designs if sailed conservative(ie: not raced in high winds under spinnaker) were excellent sea boats.

[colemj]

OK, there is always "that storm" that seems to be the primary driver for some people's boat decisions - but do those people also drive an armored SUV for the purpose of surviving "that crash"? Or live on top of a mountain to avoid "that flood"?

How far does one need to go in the "that XXX" direction? Certainly, all the boats deemed unsuitable here have done much cruising without loss of life or boat - including crossing oceans and being in snotty weather.

BTW, waterline rules, so I would much rather be on the Sense 55 than the Contessa 32 in bad weather.

Mark

[colemj]

Originally Posted by robert sailor

These older designs if sailed conservative(ie: not raced in high winds under spinnaker) were excellent sea boats.

Wait, wait, wait - you cannot pull out the 1979 Fastnet argument to make a point while at the same time avoid the 1979 Fastnet argument to make another point…

Mark

[OceanQuest]

It isn't so much manufacturers saving money on making new boats - we have computers to blame! When 'plastic' boats first appeared - GRP, Fibreglass etc - nobody was sure how much to use to make the boat strong enough to withstand all conditions, so they laid it on with a trowel!

The older Westerleys are a tribute to this, built like the proverbial brick outhouse, but as time went on they realised that they had overdone it and cautiously reduced the thickness used.

Nowadays we have computer aided design, which calculates the absolute minimum thickness of GRP (or whatever) needed for each component to be strong enough for its purpose. The result is flooring and even decks that flex when walked on. They should be safe (according to the computers), but don't feel it.

Give me an old Westerley or equivalent any day!